1. Field of the Invention
The present invention relates to a multilayered ceramic capacitor, a mounting structure of a circuit board having the multilayered ceramic capacitor thereon, and a packing unit for the multilayered ceramic capacitor.
2. Description of the Related Art
A multilayered ceramic capacitor, a multilayered chip electronic component, is a chip type condenser mounted on printed circuit boards of various electronic products, such as image devices including liquid crystal displays (LCDs) and plasma display panels (PDPs), computers, personal digital assistants (PDAs), mobile phones, and the like and implement charging or discharging of electricity.
A multilayered ceramic capacitor (MLCC) may be used as a component of various electronic products due to advantages thereof such as a small size, high capacitance, and ease of mountability.
The multilayered ceramic capacitor may have a structure in which a plurality of dielectric layers and a plurality of internal electrodes having different polarities with the dielectric layers interposed therebetween are laminated alternately with each other.
Since dielectric layers may have piezoelectric and electrostrictive properties, a piezoelectric phenomenon may occur and thus cause vibrations among the internal electrodes when AC or DC voltage is applied to the multilayered ceramic capacitor.
Such vibrations may be transferred to a printed circuit board on which the multilayered ceramic capacitor is mounted, through external electrodes of the multilayered ceramic capacitor, and the entire printed circuit board may become an acoustic reflection surface generating vibrating sound as noise.
The vibrating sound may be within an audible frequency range of 20 to 20000 Hz, and this vibrating sound provoking an unpleasant feeling in people is known as acoustic noise.
In order to reduce acoustic noise, studies have been made with regard to the direction in which internal electrodes formed in the multilayered ceramic capacitor are mounted on a printed circuit board.
More specifically, acoustic noise is further reduced when the multilayered ceramic capacitor is mounted on a printed circuit board such that internal electrodes have directionality perpendicular with respect to the printed circuit board as compared to the case in which the multilayered ceramic capacitor is mounted on the printed circuit board such that the internal electrodes are provided horizontally with respect to the printed circuit board.
However, even though the acoustic noise is measured by mounting the multilayered ceramic capacitor on the printed circuit board such that the internal electrodes are provided horizontally with respect to the printed circuit board, the noise has a predetermined level. Therefore, a method of reducing the acoustic noise is needed.